Lipitor is a brand name for atorvastatin, which is a medication used to lower cholesterol and triglycerides in the blood. According to the sources provided, there is no indication that drinking skim milk before or after taking Lipitor would cause any harmful effects or interactions.

However, it is important to note that certain foods and beverages can interfere with the absorption of Lipitor and reduce its effectiveness. For example, grapefruit and grapefruit juice should be avoided while taking Lipitor, as they can increase the amount of the drug in the bloodstream and increase the risk of side effects [2].

It is always recommended to follow the instructions provided by your healthcare provider and the medication label when taking Lipitor or any other medication. If you have any concerns or questions about how to take Lipitor, it is best to consult with your healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.webmd.com/drugs/2/drug-3330/lipitor-oral/details
[3] https://labeling.pfizer.com/showlabeling.aspx?id=587§ion=PPI